Contents

What Is REX

REX is completely plug and play flash memory upgrade. REX plugs
into the Option ROM slot, with no soldering or necessity to open
the laptop case.

REX provides support for up to 8
in-circuit selectable option roms. That means, you can have 8 different
software packages on one Option ROM, and select between them without
physically unplugging anything.

In addition, REX is in-circuit, software
reprogrammable. That means you can change, patch, or replace an Option ROM image
without any special hardware or physically unplugging REX.

REX Manager

REX comes pre-programmed with REX Manager software. REX
Manager allows you to pick which of the 8 ROM images is the one
currently in use.

REX Manager operates "behind the scenes" to make sure the currently
selected Option ROM image is automatically enabled on every power cycle.
This is an impressive trick since REX does not receive power while
the laptop is off (unlike the RAM memory circuit).

Also, REX Manager is able to do this while using a minimal amount of RAM space (about 10 bytes)!

Advanced BASIC ROM Replacement Mode (OPTIONAL)

For users with the do-it-yourself spirit, an optional
feature of REX can be enabled.

With a single wire soldered in place, REX permits BASIC ROM replacement!

This means that you can disable the built-in BASIC/TEXT/TELCOM ROM
on your motherboard and replace it with a specific block of REX flash memory.
Typically, this will be the same BASIC/TEXT/TELCOM ROM image we know and
love, with a few changes. So, you can
upgrade your Model T with little tweaks like Y2K, the lomem patch, new
character sets, put your name on the main menu, etc.

Installing REX Manager - It's Easy

From a cold restart, simply typing

CALL 63012

will install the REX system.

To start REX Manager, press and hold reset,then press and hold ESC. Keep ESC down until you have released the reset button.

Then from
basic type:

CALL 911

REX Manager will start, allowing you to manage
which ROMs stored in REX can be used, and when.

Additional Utilities

A separately loadable utility allows you to burn ROM images into REX.

Future Roadmap

Future releases of REX will have a built in file system for managing
REX files, TPDD files and RAM files.

There will be approximately 512K of
file storage.

A likely future feature is a facility for freezing/thawing RAM images to/from flash. This would offer an easy way to quickly backup all RAM to flash, or switch between multiple snapshots of RAM. This is similar to the "fast switch environments" on Remem: it would be like having multiple laptops in the same case!